Internal combustion engines having a rotary configuration can generally be classified as turbine or non-turbine. In turbine engines, a flow of combustion gases parallel to an axle impacts inclined vanes attached to the axle, causing the axle to rotate. This rotational motion is then used to perform work. This type of rotary internal combustion engine is widely accepted and used.
The field of non-turbine rotary engines has seen far less development and practical application. In this field, only eccentric rotary engines, such as the Wankel engine, have been significantly developed and used. Non-turbine rotary engines that are also non-eccentric have been proposed in numerous patents, but have not seen significant development and use to this date.